I still have not found an amp that can help a guitar player improve in more ways faster. It has a computer in it that allows it to record, play jam tracks created by live people in studios. You can speed them up or slow them down or change the key the amp plays them back in. It has a two inch tweeter built in just for playing music back through so you can get the high notes you don't really get from a 12 inch speaker. You can record yourself over the jam tracks. Record a song you made up and jam to it.
Check out some youtubes on it.
It is a 75 w. amp with a 12 inch speaker. They cost $400.00 new from what I see. I've had mine for a little over two years and would save to buy another if I lost it.